Single radiation ray path for thermographic imaging and transfixing or fusing

ABSTRACT

A copying machine is provided wherein a heat image is formed on a heat sensitive intermediate member at an imaging station by exposing the same and an original to a radiation source, then moving the intermediate in one direction to a developing station and developing the image thereon with toner particles, and then reversing the direction of movement of the intermediate back along the same path to the imaging station whereat a copy medium is brought into engagement with the developed image and heat is applied thereto by the same radiation source and the developed image transferred to the copy medium. Rather than transfer the developed image to a copy paper, the toner particles may be fixed or fused to the heat sensitive member, if desired.

United States Patent 1 1111 3,904,875

Rees et al. Sept. 9, 1975 [54] SINGLE RADIATION RAY PATH FOR 3,684,372 8/1972 Limberger 355/100 THERMOGRAPHIC IMAGING AND TRANSFIXING OR FUSING Inventors: James D. Rees, Pittsford; James A. Critchlow, Macedon, both of NY.

Assignee: Xerox Corporation, Stamford,

Conn.

Filed: Dec. 27, 1973 App]. No.: 428,957

References Cited UNITED STATES PATENTS 7/1966 Dulmage 250/317 11/1971 Haugen 355/27 7/1972 Jarvis 101/470 Primary Examiner-James W. Lawrence Assistant E.raminerD. C. Nelms [57] ABSTRACT A copying machine is provided wherein a heat image is formed on a heat sensitive intermediate member at an imaging station by exposing the same and an original to a radiation source, then moving the intermediate in one direction to a developing station and developing the image thereon with toner particles, and then reversing the direction of movement of the intermediate back along the same path to the imaging station whereat a copy medium is brought into engagement with the developed image and heat is applied thereto by the same radiation source and the developed image transferred to the copy medium. Rather than transfer the developed image to a copy paper, the toner particles may be fixed or fused to the heat sensitive member, if desired.

28 Claims, 5 Drawing Figures PATENTEU 9 75 SHIT 1 BF 2 SINGLE RADIATION RAY PATH FOR THERMOGRAPHIC IMAGING AND TRANSFIXING ()R FUSING Applicant Serial No. Filing Date Lincoln First Bank of Rochester Executor for Roger H. Iiichorn Lincoln First llank of Rochester, Executor for Roger H. l-lichorn Lincoln First Bank of Rochester. Executor for Roger H. I-iiehorn Myron J. I.enhard Lincoln First Bank of Rochester, [Executor for Roger H. liichorn Lincoln First Bank of Rochester, Executor for Roger H. Eichorn DESCRIPTION OF THE INVENTION In many thcrmographic processes, a heat image is impressed upon a thermal sensitive member at an imaging station and. that image is then developed with toner particles at a development station, and the developed or toned image is finally either fused to the heat sensitive material or transfixed (transferred and fused) to a copy medium at a fusing or transfixing station. Usually separate radiation sources are utilized for the imaging function and the fusing or transfixing function. In some systems, the same radiation source is utilized for both functions, but in those instances the two functions are conventionally carried out at separate stations.

If the imaging and fusing or transfixing stations are equipped with separate radiation sources. separate control mechanisms and transport mechanisms must be provided. and those mechanisms must be synchronized so that the functions at each station are efficiently carried out. Obviously, this requires duplication of parts and a more complicated system.

When the same radiation source is provided for both stations. part of the web intermediate or heat sensitive material is wasted since a new portion of the web is exposed to the radiation source when the imaged portion of the web is being fused or transfixed. Furthermore. one is limited to the same radiation intensity for both functions. or otherwise the machine must be larger so that the radiation intensity may be changed to a different intensity for either fusing or transfixing after imaging.

It is an object of this invention to provide a copying method which permits the use ofan inexpensive, simple and compact copying device in which there is little. if

any, waste of the heat sensitive material.

It is proposed to accomplish the above object by using the same radiation source and station for imaging and fusing or transifixing functions.

Other objects of this invention will become apparent when the following description is read in conjunction with the attached drawings wherein:

FIG. I is a simplified perspective view of a copying apparatus for carrying out the present invention;

FIG. 2 is a view of a gear mechanism for coordinating movement of the web take-up and feed rolls and the developing apparatus;

FIG. 3 is a fragmentary sectional view of the copying apparatus as seen during an imaging function;

FIG. 4 is a fragmentary sectional view of the copying apparatus as seen after an image on a web has been developed. and

FIG. 5 is a fragmentary sectional view of the copying apparatus as seen during transfer and fixing of a powder image from the web to a copy sheet.

Referring to FIGS. 1 and 2, there is illustrated a copying apparatus having a main frame It) with the front cover removed to show the essential elements thereof. Attached to the main frame It) are a take-up shaft 12, a feed shaft I4 and a pair of-idler rolls l6 and I8. A rotatable shaft 20 is located between the take-up roll I2 and the feed roll I4 and has a hand crank 22 fixedly attached thereto at the front end thereof and a drive gear 24 attached to the rear end thereof. Gears 26 and 28 are fixed to the take-up shafts l2 and I4., respectively. and mesh with the drive gear 24 which is located therebetween. A slip clutch (not shown) is provided to con nect the gear 28 with the shaft I4 whereby upon clockwise rotation of the gear 28, the shaft I4 will be rotated and upon counterclockwise rotation of the gear 28. the gear will slip in relation to the shaft I4. A slip clutch (not shown) interconnects the gear 26 with the take-up shaft I2 whereby upon counterclockwise rotation of the gear 26, the take-up shaft will be rotated and upon clockwise rotation ofthe gear 26, the gear will slip relative to the shaft I2.

A chamber comprising an upper curved wall 30, which is a specular or diffuse reflector. side walls 32 and a bottom radiation transparent glass wall 34 is also fixed to the frame 10 and contains therein a pulsed or continuous radiation source, such as a xenon flash lamp or an incandescent lamp 36. The reflector is so designed to distribute the radiation from the lamp 36 uniformly. This chamber will hereinafter be referred to as a combined imaging and transfixing station.

A development station is provided comprising a reservoir of ferromagnetic toner particles 38 and a well known magnetic brush 40 which is mounted on the front and rear walls of the reservoir to rotate through the toner particles. A gear 42 is mounted to the rear end of the magnetic brush 40 and intcrmcshes with a rotatable drive transfer gear 44. Rotatable motion of drive gear 24 is imparted to the transfer gear 44 through a link 46 which interconnects gears 24 and 44. Countcrclockwise rotation of the gear 44 will cause clockwise rotation of the gear 42 and thereby the magnetic brush 40. while clockwise rotation of the gear 44 will cause counterclockwise rotation of the gear 42 and thereby counterclockwise rotation of the magnetic brush 40.

A web supply roll is secured to the feed shaft I4. Estending from the supply roll there is a web 48 which runs under the glass member 34, over the magnetic brush 40 and to the take-up shaft 12. The web 48 comprises a support coated with a heat sensitive material. For example. the support may be an organic film such as a polyester film, cellulose acetate or triacetate. film coated with a delayed tack adhesive which is normally hard and non-tacky at room temperature, but which, upon being activated by heat to a tacky condition and subsequently cooled to room temperature, thereafter remain tacky for considerable periods of time varying from at least 30 seconds to several days or .more depending upon the particular composition involved. Such delayed tack coatings are well known and can be a mixture of discrete particles ofresin, such as indene resin or esterified resin, and discrete particles of crystalline plasticizer, such as diphenyl phthalate or N- cyclohexyl paratoluene sulfonamide. The particles are bound together into the supporting film by a binder, such as styrene-butadiene copolymer. Generally speaking, the crystalline plasticizer component of the mixture is in excess of the resin component.

The toner particles 38 comprise thermoplastic particles pigmented with carbon black or other radiation absorbing dyes of pigments, and mixed with iron oxide particles.

A pressure plate 50 has a pair of pins 52 at the front and rear sides (not shown) thereof which extend through separate slotted guide member 54 (which are secured to the frame for vertical. slidable movement. A plurality of coil springs 56 are located between the bottom wall of the support frame 10 and the bottom of the pressure plate 50 to urge the pressure plate 50 downwardly away from the glass member 34. A shaft 58 is rotatably mounted on the frame 10 below the pressure plate 50 and has a pair of eccentric cams 60 fixed thereto. The cams 60 engage the bottom surface of the pressure plate 50 at the front and rear thereof. A hand crank 62 is fixed to the front end of the shaft 58 for rotating the cams 60. A removable tray 64 is provided which may be slid in between the pressure plate 50 and the glass plate 34 to then rest on the pressure plate 50. The tray 63 is constructed to fasten an original or a copy sheet on the top surface thereof for the purposes of this invention and to facilitate separation of the sheet from the web should there be any tendency of sticking therebetween. Upon rotation of the cams 60, the pressure plate 50 will be moved upwards against the action of the springs 56 until a sheet on the tray 63 engages the web 48 and presses the same against the glass plate 34.

In operation, a fresh portion of web 48 is brought into alignment with the imaging and transfixing station by turning the crank 22 in a clockwise direction. An original sheet 64 having an image thereon is placed onto the tray 63 and the cams 60 are manually rotated to move the pressure plate 50 and the tray 63 upwards, thereby bringing the original sheet into contact with the heat sensitive layer of the web 48. The lamp 36 is energized to expose the web and the original image, thereby heating the heat sensitive layer in the areas corresponding to the image to form a tacky image thereon. The lamp 36 is turned off and then the cams 60 are rotated to allow the springs 56 to release the tray 63. The tray 63 is thereafter removed from the apparatus, thereby separating the original sheet from the web 48. The crank 22 is then rotated in a clockwise direction thereby driving take-up shaft 12 to move the web 48 past the developer station where the magnetic brush 40 brushes toner particles 38 onto the web 48 to develop the tacky areas thereon corresponding to the image. After the image has been developed, the crank 22 is turned in the opposite direction .to drivethe feedroll 14 in a clockwise direction to reverse the direction of travel of the web 48 and bring the developed image back to the imaging and transfixing station.

A copy sheet 66 is placed onto the tray 63 which, in turn, is remounted on the pressure plate 50. The cams 60,are then turned to lift the pressure plate 50 and the tray 63 upwardly to thereby press the copy sheet against the developed image on the web 48. The lamp 36 is then energized to heat the toner particles whereby a substantial portion thereof are transfixed (transfer and fixed) to the copy sheet to provide a reproduction of the original image. This transfixing occurs due to the pressure between the web 48 and the copy sheet 66 combined with a corresponding proper temperature. Thereafter, the cams are rotated again to release tray 63, and the tray is then removed thereby separating the copy sheet 62 from the web with a copy of the original image thereon. After the copy sheet has been separated from the web 48, the crank 22 is turned in a clockwise direction to move the used portion of the web 48 out of the combined imaging and transfixing station and to bring an unused portion of the web 48 into alignment with the imaging and transfixing station in preparation for another copying circle during which the above steps are repeated.

Rather than transferring the developed image to a copy paper, the developed image may be fused onto the heat sensitive web 48. This may be desired when a series of copies are needed in a specified sequence and a savings of copy paper is desired. In that event, the copy paper is eliminated and the lamp 36 is energized to fuse the toner particles to the web with the tray 63 either removed 'or in a released position. When that is done, the combined imaging and transfixing station becomes a combined'imaging and fusing station.

From the above, it can be seen that this process permits a compact and simple copying apparatus to be used. Moreover, it will be appreciated that lamp intensities can be used for each of the functions without increasing the size of the machine.

What is claimed is:

1. An image copying method comprising the steps of:

exposing a heat sensitive member having a delayed tack adhesive coating at a first station to an imagelike pattern of thermal radiation from a radiant source, thereby thermally imparting said image to said member.

moving the imaged member in one direction to a de velopment station,

developing said image at said development station,

moving the member with the developed image in the opposite direction back into said first station, and re-exposing said member to thermal radiation from said source to fix said image.

2. A method as recited in claim 1 further comprising the step of holding a copy medium in pressure contact with the developed image while said member is being reexposed, whereby said image is transfixed onto said copy medium.

3. A methodas recited in claim 1 wherein the heat sensitive member travels back and forth in a predetermined path while moving in said one direction and said opposite direction.

4. A method as recited in claim 2 wherein the heat sensitive member passes the development station while moving in each of said directions.

5. A method as recited in claim 2 wherein the image on the heat sensitive member is developed with toner particles.

6. A method as recited in claim 2 wherein the copy medium is brought into engagement with the developed image after the heat sensitive member has been moved back into said first station, and the transfixing of the developed image onto the copy medium takes place while the heat sensitive member and copy medium are sta tionary. Y

7. A method as recited in claim 2 wherein said image is imparted to said heat sensitive member by exposing said heat sensitive member, and an original bearing said image, to radiation from said source while said heat sensitive member and said original are stationary.

8. A method as recited in claim 2 wherein said heat sensitive memberis a web which is fed from a supply roll to a take-up roll when moved in said one direction and from the take-up roll to the supply roll when moved in the opposite direction, said method further comprising the step of moving the web in said one direction to move an unused portion thereof into position to make a new copy in preparation for each successive copying cycle.

9. A method as recited in claim 1 wherein the developed image is fixed to the heat sensitive member when said member is re-exposed to radiation from said source.

10. A method as recited in claim 9 wherein the heat sensitive member travels back and forth in a predetermined path while moving in said one direction and said opposite direction.

11. A method as recited in claim 9 wherein the heat sensitive member passes the development station while moving in each of said directions.

12. A method as recited in claim 9 wherein the image on the heat sensitive member is developed with toner particles.

13. A method as recited in claim 9 wherein the heat sensitive member is stationary while said image is being fixed.

14. A method as recited in claim 9 wherein said image is imparted to said heat sensitive member by exposing said heat sensitive member, and an original bearing said image, to radiation from said source while said heat sensitive member and said original are stationary.

15. A method as recited in claim 9 wherein said heat sensitive member is a web which is fed from a supply roll to a take-up roll when moved in said one direction and from the take-up roll to the supply roll when moved in the opposite direction, said method further comprising the step of moving the web in said one direction to move an unused portion thereof into position to make a new copy in preparation for each copying cycle.

16. A thermographic copier comprising the combination of a first station including a radiant source,

a development station spaced from said first station,

means for moving a heat sensitive member having a delayed tack adhesive coatiing back and forth along a predetermined path extending between said first station and said development station, means for exposing said heat sensitive member to an imagewise pattern of radiation from said source during a first pass of said member through said first 6 station to thereby thermally impart an image to said member, means for developing said image at said development station, and 5 means for re-exposing said heat sensitive member to radiation from said source during a second pass of said member through said first station to thereby fix the developed image.

17. The copier of claim 16 wherein said first station further includes means for holding an original bearing an image in pressure contact with said heat sensitive member while said heat sensitive member is being exposed, whereby the image imparted to said heat sensitive member corresponds to the image of said original.

18. The copier of claim 17 wherein said means for holding said original and said heat sensitive member in pressure contact comprises a radiation transparent member positioned between the radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said original between said pressure plate and said path, and means for movingsaid pressure plate toward and away from said transparent member.

19. The copier of claim 16 wherein said first station further includes means for holding a copy medium in pressure copy contact with the developed image on said heat sensitive member while said heat sensitive member is being re-exposed, whereby the developed image is transfixed onto said copy medium.

20. The copier of claim 19 wherein said means for holding said copy medium and said heat sensitive member in pressure contact comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said copy medium between said pressure plate and said path, and means for moving said pressure plate toward and away from said transparent member.

21. The copier of claim 16 wherein said first station further includes a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for moving said pressure plate toward and away from said transparent member, means for sandwiching an original bearing an image between said pressure plate and said heat sensitive member while said heat sensitive member is being exposed such that the image imparted to said heat sensitive member corresponds to the image of said original, and means for sandwiching a copy medium between said pressure plate and the developed image on sa'd heat sensitive member while said heat sensitive member is being reexposed such that the developed image is transfixed onto said copy medium.

22. The copier of claim 16 wherein said heat sensitive member is a web; and said copier further includes a supply roll and a take-up roll attached to said web upstream and downstream. respectively, of said first station and said development station, and reversible drive means coupled to said web so that a given portion of said web is sequentially available during each copying cycle for imaging at said first station, development of said image at said second station, and fixing of said image back at said first station.

23. The copier of claim 22 wherein said first station further includes means for holding an original bearing an image in pressure contact with said portion of said 7 web during the exposure thereof, whereby the image imparted to said portion of said web corresponds to the image of said original.

24. The copier of claim 23 wherein said means for holding said original in pressure contactwith said portion of said web comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said original between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.

25. The copier of claim 22 wherein said first station further includes means, for holding a copy medium in pressure contact with the developed image on said portion of said web while said portion is being re-exposed, whereby said image is transfixed onto said copy medium.

26. The copier of claim 25 wherein said means for holding said copy medium in pressure contact with the developed image on said portion of said web comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said copy medium between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.

27. The copier of claim 22 wherein said first station further includes means for holding selected documents in pressure contact with said portion of said web while said portion is being exposed and re-exposed; said document holding means comprising a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate supported on the opposite side of said path, means for supporting a selected document between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.

28. The copier of claim 27 wherein said selected document is an original bearing an image when said portion of said web is being exposed and a copy medium when said portion of said web is being re-exposed, whereby an image corresponding to the image of said original is imparted to said portion of said web and subsequently transfixed in developed form onto said copy medium. 

1. AN IMAGE COPYING METHOD COMPRISING THE STEPS OF: EXPOSING A HEAT SENSITIVE MEMBER HAVING A DELAYED TACK ADHESIVE COATING AT A FIRST STATON TO AN IMAGE-LIKE PATTERN OF THERMAL RADIATION FROM A RADIANT SOURCE, THEREBY THERMALLY IMPARTING SAID IMAGE TO SAID MEMBER. MOVING THE IMAGED MEMBER IN ONE DIRECTION TO A DEVELOPMENT STATION, DEVELOPING SAID IMAGE AT SAID DEVELOPEENT STATION, MOVING THE MEMBER WITH THE DEVELOPED IMAGE IN THE OPPOSITE DIRECTION BACK INTO SAID FIRST STATION, AND
 2. A method as recited in claim 1 further comprising the step of holding a copy medium in pressure contact with the developed image while said member is being reexposed, whereby said image is transfixed onto said copy medium.
 3. A method as recited in claim 1 wherein the heat sensitive member travels back and forth in a predetermined path while moving in said one direction and said opposite direction.
 4. A method as recited in claim 2 wherein the heat sensitive member passes the development station while moving in each of said directions.
 5. A method as recited in claim 2 wherein the image on the heat sensitive member is developed with toner particles.
 6. A method as recited in claim 2 wherein the copy medium is brought into engagement with the developed image after the heat sensitive member has been moved back into said first station, and the transfixing of the developed image onto the copy medium takes place while the heat sensitive member and copy medium are stationary.
 7. A method as recited in claim 2 wherein said image is imparted to said heat sensitive member by exposing said heat sensitive member, and an original bearing said image, to radiation from said source while said heat sensitive member and said original are stationary.
 8. A method as recited in claim 2 wherein said heat sensitive member is a web which is fed from a supply roll to a take-up roll when moved in said one direction and from the take-up roll to the supply roll when moved in the opposite direction, said method further comprising the step of moving the web in said one direction to move an unused portion thereof into position to make a new copy in preparation for each successive copying cycle.
 9. A method as recited in claim 1 wherein the developed image is fixed to the heat sensitive member when said member is re-exposed to radiation from said source.
 10. A method as recited in claim 9 wherein the heat sensitive member travels back and forth in a predetermined path while moving in said one direction and said opposite direction.
 11. A method as recited in claim 9 wherein the heat sensitive member passes the development station while moving in each of said directions.
 12. A methoD as recited in claim 9 wherein the image on the heat sensitive member is developed with toner particles.
 13. A method as recited in claim 9 wherein the heat sensitive member is stationary while said image is being fixed.
 14. A method as recited in claim 9 wherein said image is imparted to said heat sensitive member by exposing said heat sensitive member, and an original bearing said image, to radiation from said source while said heat sensitive member and said original are stationary.
 15. A method as recited in claim 9 wherein said heat sensitive member is a web which is fed from a supply roll to a take-up roll when moved in said one direction and from the take-up roll to the supply roll when moved in the opposite direction, said method further comprising the step of moving the web in said one direction to move an unused portion thereof into position to make a new copy in preparation for each copying cycle.
 16. A thermographic copier comprising the combination of a first station including a radiant source, a development station spaced from said first station, means for moving a heat sensitive member having a delayed tack adhesive coatiing back and forth along a predetermined path extending between said first station and said development station, means for exposing said heat sensitive member to an imagewise pattern of radiation from said source during a first pass of said member through said first station to thereby thermally impart an image to said member, means for developing said image at said development station, and means for re-exposing said heat sensitive member to radiation from said source during a second pass of said member through said first station to thereby fix the developed image.
 17. The copier of claim 16 wherein said first station further includes means for holding an original bearing an image in pressure contact with said heat sensitive member while said heat sensitive member is being exposed, whereby the image imparted to said heat sensitive member corresponds to the image of said original.
 18. The copier of claim 17 wherein said means for holding said original and said heat sensitive member in pressure contact comprises a radiation transparent member positioned between the radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said original between said pressure plate and said path, and means for moving said pressure plate toward and away from said transparent member.
 19. The copier of claim 16 wherein said first station further includes means for holding a copy medium in pressure copy contact with the developed image on said heat sensitive member while said heat sensitive member is being re-exposed, whereby the developed image is transfixed onto said copy medium.
 20. The copier of claim 19 wherein said means for holding said copy medium and said heat sensitive member in pressure contact comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said copy medium between said pressure plate and said path, and means for moving said pressure plate toward and away from said transparent member.
 21. The copier of claim 16 wherein said first station further includes a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for moving said pressure plate toward and away from said transparent member, means for sandwiching an original bearing an image between said pressure plate and said heat sensitive member while said heat sensitive member is being exposed such that the image imparted to said heat sensitive member corresponds to the image of said original, and means for sandwiching a copy medium between said pressure plate and the developed image on said heat sensitive member while said heat sensitive member is beIng re-exposed such that the developed image is transfixed onto said copy medium.
 22. The copier of claim 16 wherein said heat sensitive member is a web; and said copier further includes a supply roll and a take-up roll attached to said web upstream and downstream, respectively, of said first station and said development station, and reversible drive means coupled to said web so that a given portion of said web is sequentially available during each copying cycle for imaging at said first station, development of said image at said second station, and fixing of said image back at said first station.
 23. The copier of claim 22 wherein said first station further includes means for holding an original bearing an image in pressure contact with said portion of said web during the exposure thereof, whereby the image imparted to said portion of said web corresponds to the image of said original.
 24. The copier of claim 23 wherein said means for holding said original in pressure contact with said portion of said web comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said original between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.
 25. The copier of claim 22 wherein said first station further includes means for holding a copy medium in pressure contact with the developed image on said portion of said web while said portion is being re-exposed, whereby said image is transfixed onto said copy medium.
 26. The copier of claim 25 wherein said means for holding said copy medium in pressure contact with the developed image on said portion of said web comprises a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate disposed on the opposite side of said path, means for supporting said copy medium between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.
 27. The copier of claim 22 wherein said first station further includes means for holding selected documents in pressure contact with said portion of said web while said portion is being exposed and re-exposed; said document holding means comprising a radiation transparent member positioned between said radiant source and one side of said path, a pressure plate supported on the opposite side of said path, means for supporting a selected document between said pressure plate and said path, and means for moving said pressure plate towards and away from said transparent member.
 28. The copier of claim 27 wherein said selected document is an original bearing an image when said portion of said web is being exposed and a copy medium when said portion of said web is being re-exposed, whereby an image corresponding to the image of said original is imparted to said portion of said web and subsequently transfixed in developed form onto said copy medium. 